My personal feeling is that this website needs to adjust its pricing for farmed items, such as vegetables. Currently, the calculator is making the assumption that every field will make a single fair crop. This, while simple, isn't true. Poor and Fair Crops have various chances to drop, in varying quantities, let alone any critical items that may appear.

Now, any formulas or averages for farmed items, while accurate over the long haul, will probably be substantially off in low quantities. So how do we reconcile these two approaches? Pessimism.

The best idea I have for a meeting between accurate and simple is to find out how often there is no Fair Crop from a field, and increase the total cost for that field by a related factor. For example, say a Fair Crop was missing 15% of the time. If you take the cost of one Field and divide it by .15, then that would be representative of the amount of money you have to spend, on average, to get your crop.

Just a few initial thoughts here - using the guiding principle that it's better to overestimate, rather than underestimate cost.

Thank you for your suggestions. We've taken what you said into consideration and performed some initial, and very small-scale, in-game testing (performed and financed by Nav) as well as consulting a number of farmers as to numerical yields.

Farming, as you are probably well aware, appears to yield crops randomly as opposed to by some specific chance value . This makes any algorithmic approach to defining an exact number impossible, so the best method of showing a number of farming ingredients for people to use is to make estimates.
We aren't sure what the best value to use is, but from our testing it appears that a 1:1 ratio (Farming Recipe:Fair Crop Yield) gives a reasonable amount of accuracy given the random nature of the results. In many of our tests the number of crops received exceeded the number specified by the calculator

Keep in mind that the original intent behind this calculator was to give users a list of all the ingredients they require to ultimately make the number of result items they specified, and displayed in an easily readable way. The creator, Nav, thought that this would be helpful if people wanted to find or buy ingredients so that their friends or members of their Kinship could help them to craft items that may require skills that their characters lacked. We feel that drop chances or recipe result chances go beyond the intent of this project.

It is fair to say, though, that displaying ingredients in a way that assumes 1 Fair Crop per Field can be misleading, so we've added a small disclaimer for all Farming recipes and recipes that have Farmed components.